The present invention relates to a processing apparatus which has a cooling sample stage allowing reduction of thermal drift and which uses a focused charged particle beam.
In recent years, in preparing a sample for an electronic microscope in order to observe a particular area such as observing a defective part of a semiconductor device, a method of using a charged particle beam is utilized. More specifically, a sample is processed in such ways that ions are accelerated, focused and applied onto a particular area of a device or the like to be an observation target and a desired slice is cut out, and that a sample is cut to provide desired depth or a shape in order to expose an observation part when an observation target exists inside.
When a sample to be an observation target is a material vulnerable to heat, it is necessary to process the sample while it is being cooled. In addition, charged particle beam irradiation often damages a sample, but it is reported that a sample is cooled to reduce damage caused by a charged particle beam.
At present, when a sample is cooled in a charged particle beam processing apparatus, a sample state is cooled for processing. Here, typically, when a sample is cooled, the entire sample stage is cooled. However, when the entire sample stage is cooled, problems arise that it takes a long time to stabilize the temperature of a sample, and that cooling the entire sample tends to generate a temperature gradient and thus a drift tends to occur caused by thermal expansion and contraction, causing highly accurate processing to be difficult. For the measures against the drift, there is a method in which the temperature of a sample is set to a desired temperature beforehand and the structure of the surface and the cross section and the information of the sample are acquired for accurate observation or processing. However, the equipment becomes in a large scale, and the method is not a convenient method for solving problems.
[Patent Reference 1] JP-A-2003-194746
The invention has been made in view of the circumstances. An object is to provide a processing apparatus which uses a focused charged particle beam and which can promptly cool a sample, reduce a thermal drift, suppress a position shift caused by thermal expansion and contraction, and improve processing accuracy.